We all expected this. After seeing the popularity of SRAM’s 1x12 Eagle group, Shimano needed to respond in a big way with a drivetrain that matched the performance and simplicity of its competitor. This is the response: the new XTR M9100 1x12 (and/or 2x12) drivetrain.

Time will tell how the new XTR performs–members of the North American media will get their first rides on the group in mid-June–but on paper, the group looks impressive, and reports from insiders at bike brands who have ridden the new XTR are extremely positive. Shimano’s resources and capabilities should never be underestimated.

There are new parts as well that reflect the continued evolution of XTR from—when first launched in 1991—a strict XC race group to a group for any mountain biker seeking “the best stuff” for almost all forms of mountain biking: a chain guide and dropper-post remote.

While XTR’s premium price puts it out of reach for many riders, everyone should pay attention to the new XTR because of Shimano’s well-established practice of trickling down the major features of XTR to XT, SLX, Deore. There’s some stuff here–specifically the cassettes–that perhaps could be adopted by future Shimano drop-bar groups for gravel, cyclocross, and maybe even road: Might we see XTR’s new cassette driver in next-gen Dura-Ace?

If you prefer tighter jumps between cogs, that’s found in the 10-45 cassette (450 percent range). Cog progression: 10-12-14-16-18-21-24-28-32-36-40-45.

Either way, the cassettes employ a new mounting hub/cassette interface standard called Micro Spline. Immediately noticeable are more and smaller splines compared with Shimano’s 9/10 and 11-speed driver bodies. This is said to prevent the familiar gauging of aluminum driver bodies by discreet cassette cogs.

The cassette feature Shimano’s new Micro Spline interface

Matt Phillips

Less noticable: The Micro Spline driver is designed to accommodate a 10-tooth cog. The diameter of Shimano’s longstanding 9/10/11-speed driver prevented the use of cogs smaller than 11 teeth (unless, as found in some aftermarket cassette options, the teeth were integrated into the cassette lockring). So, Shimano needed to revamp its driver to accommodate the 10-tooth (SRAM’s XD driver was developed for the same reason).

There’s also a lightweight, 11-speed cassette option (details below).

All XTR 9100 cassettes have new Hyperglide+ tooth profiles, which “guides the chain both up and down the cassette, providing faster, smoother shifting in both directions.”

There's Still a 2x Option

Assuming you can find a current mountain bike frame that can accommodate a front derailleur, you can get your kicks with new XTR. The M9100 derailleur uses the “side swing” mechanism that debuted in the previous generation of XTR, and is offered in several mounting styles.

One of this group's bigger surprises is a new style of front shifter. It has a single paddle, which the rider pushes (small- to big-ring shift) or pulls (big to small shift). The rear shifter still uses Shimano’s familiar dual-paddle design.

The new cassette has 51 teeth and a huge gear range.

Courtesy of Shimano

Just one ring combination is offered for 2x12: 28/38. The new XTR cranks use direct-mount chainrings, and so can be easily swapped between 1x and 2x options.

New Rear Derailleurs With a Touch of the Old

Underneath the new styling, the XTR rear derailleurs carry over the predominant features of the previous generation. These include the low-profile Shadow design and the one-way pulley-cage clutch (with on/off lever). New, larger, 13-tooth pulleys are employed.

Surprisingly, the intermediate link that offered compatibility with rear-set “direct mount” rear derailleur hangers has been eliminated in this generation of XTR. It’s doubly surprising because the direct mount–compatible design–which debuted in Shimano’s mountain bike products–had just been incorporated into the latest Dura-Ace, Ultegra, and 105 road groups. A Shimano representative said the new (old) rear derailleur mounting format was necessary to properly position the derailleur for shifting the 10-51 cassette. Eliminating the link probably stiffens up the derailleur platform, and might save a few grams too.

A new design makes it easier to shift into the 51-tooth rear.

Matt Phillips

Three rear derailleurs are offered. The RD-M9100-SGS has the longest pulley cage and is required for use with the 10-51 cassette, but is also compatible with the 10-46 cassette. The RD-M9100-GS has a 28mm shorter pulley cage, for less weight and more ground clearance, but is compatible only with the 10-46 cassette. The RD-M9120-GS is for use with a double-chainring drivetrain.

Chain Tech and New Chain Tools

The shift (ha!) to 12 speeds brings with it a new 12-speed chain, of course. The news here is a longer inner link plate, which does a whole bunch, according to Shimano’s product information. “The new design reduces natural vibrations normally caused by the inner and outer chain plates rolling onto the chainring and provides better chain engagement, stronger retention, and smoother pedaling.” Damn!

The chain’s link plates are shaped to help smooth shifts.

Matt Phillips

And if there’s a new chain, there are new chain tools. While it’s likely that many existing chain tools will work with the 12-speed chain, Shimano officially recommends using its new 12-speed-specific tools. Two versions are offered: a consumer-level tool for $70 and a shop-quality tool for $160.

A chain tool won’t be required for routine maintenance and cleaning, however: The new XTR chain utilizes a quick-link for connection.

Familiar Aluminum Cranks, but a Few Surprises Too

Like other recent XTR generations, the new XTR crankarms are hollow aluminum, while the brand’s familiar 24mm steel crank axle is carried over as well.

The most exciting news about the new XTR crank is that Shimano finally adopted a direct mount system for the chainrings, which eliminates the need for a two-piece spider and ring design, and makes replacing/changing ring size quite easy.

The mounting system accommodates either single rings–offered in 30, 32, 34, 36, and 38-tooth, or the 28/38 double-ring combo.

XTR cranks are (still) hollow aluminum and (still) use a 24mm axle.

Matt Phillips

All cranks are offered in two Q-factors/stance widths: 162mm and 168mm. The cranks are sold with either a single ring or the 28/28 double combination.

The single-ring cranks, in both Q-factors, are compatible with either 142mm or 148mm (Boost) rear spacing. With double rings, the 162mm Q-factor crank is for 142mm spacing; if you want double rings and Boost spacing, you’ll need to run the 168mm Q-factor cranks.

The preload cap and dual-pinch bolt system used by XTR M9000 to attach the the non-drive crank has been eliminated in favor of a self-extracting single bolt system that both installs and removes the crank arm– it's the same kind of system used by SRAM, FSA, and others. A preload ring on the non-drive arm takes up any play.

Updated Rear Shifter

I noted the new single-lever front shifter above. Rear shifters, meanwhile, gain a click, but otherwise retain the dual-paddle format from the previous generation of XTR, with push or pull upper (cable release) paddle. Action is said to be lighter, with “35 [percent] less shifting operation force compared to M9000.” The product notes also say “20 [percent] quicker lever access time,” which basically means they’re easier to reach.

The shifter can be used for 11 or 12-speed XTR M9100 drivetrains

Matt Phillips

Matching Dropper Post Remote

Shimano is offering its own dropper post remote, which promises similar shape and ergonomics as its shift levers and is compatible with most droppers that clamp the cable at the lever end. Its product code, SL-MT800-IL, indicates it’s not an XTR-level part but rather an XT-level “nonseries” component.

The “XTR” dropper post remote can be direct mounted to the XTR brake.

Matt Phillips

Chain Guide For Extra Security

The other MT800-level part launching with XTR is a lightweight chain guide for single chainring. Loosening a single bolt allows adjustment of both height and chainline. Three mounting formats are offered: ISCG ’05, direct-mount, and e-type. The latter two are front-derailleur mounting standards.

A chainguide provides extra security in demanding terrain.

Matt Phillips

Enduro and XC Tuned Brake Options

XTR is still offered as a group (not just a drivetrain), which means XTR-branded disc brakes are available.

Two brake styles are offered: one weight-optimized, the other more powerful.

The 9100 brake is a two-piston model for XC-style use: It’s 26 grams lighter than the previous generation 9000-series XC brake. Like the previous generation, the XC brake lever is stripped of features to save weight and requires a hex wrench for reach adjustment.

The four-piston enduro brake system is designed for power, modulation, and heat management.

Matt Phillips

The 9120 brake is a four piston “enduro” brake that’s claimed to be as powerful as Shimano’s Saint downhill brake, though the product notes claim the XTR enduro brake has more modulation than the Saint brake. In fact, this caliper can use the same pads as the Saint caliper. The enduro brake lever has tool-free reach adjustment and adjustable lever throw.

Both levers feature a revised handlebar clamp and brace claimed to stiffen the system for improved braking feel and performance.

An updated version of Shimano’s finned, three-layer (aluminum core with steel braking surfaces) rotor is introduced with 9100 XTR with “heat-dissipating paint on exposed aluminum layer segments,” claimed to lower operating temperatures. The 140 and 160mm rotors are XC-oriented and made light, while the 180 and 200mm are enduro-oriented, with a greater focus on heat dissipation.

The XTR 4-pistion brake system’s lever has a stiffening brace.

Matt Phillips

I-SPEC EV Integrated Clamping System

The shifters and brake levers are offered in discreet clamps. But if you prefer a cleaner cockpit, the shifters and dropper remote can be integrated with the brake lever’s bar clamp using Shimano’s I-SPEC EV system. This is claimed to provide the shifters/dropper remote 14 millimeters of inboard/outboard adjustment and 60 degrees of rotational adjustment.

Lightweight 11-Speed Option

Buried among the 12-speed news is information about a lightweight 1x11-speed drivetrain option. The only unique part required for this option is the 11-speed, 10-45 cassette (cog progression: 0-12-14-16-18-21-24-28-33-39-45). The cassette mounts to the same Micro Spline hub driver as the 12-speed cassette, and this option utilizes the same derailleur, crank, chain, and shifter as 12-speed XTR. A switch on the rear shifter changes it from 12-speed to 11-speed mode (or vice versa)—similar to how some Shimano mountain bike front-derailleur shifters could be toggled between 2x and 3x modes.

According to claimed weights, this 1x11-speed option saves up to 76 grams compared with XTR 1x12. Most of the weight is saved in the cassette–the 11-speed cassette is 57 grams lighter than the 12-speed cassette–but also because of a shorter chain and other small factors.

A special rear hub compatible only with the 11-speed cassette (called the FH-M9125-B) has its drive-side flange shifted 4.7mm outboard compared to the 12-speed-compatible XTR hubs, and is claimed to provide, “improved durability through more balanced spoke tension and more rigidity with wider spoke bracing.” The 11-speed hub is also three grams lighter than the 12-speed hub. The FH-M9125-B is offered only in Boost spacing (12x148mm) but in 28- or 32-hole drillings.

With 12-speed XTR, Shimano finally has something to compete against SRAM’s Eagle

Matt Phillips

No More XTR Wheelsets

When I noticed wheelset information was not contained in the provided product information (Shimano has offered XTR wheelsets with the last several generations of XTR), I contacted a Shimano representative and asked if XTR wheelsets were coming. She said, “No XTR wheelsets. Shimano decided to focus on the thing they do best, and that is developing and executing the new freehub design.”

However, the representative did confirm that Shimano will license the Micro Spline cassette-driver design to DT Swiss (similar to what SRAM does with its XD driver). DT Swiss wheelsets are widely spec’d on high-end bikes (Yeti and Pivot, for example), and the company’s hubs are used by Enve. In addition, DT Swiss also provides guts to many companies: Bontrager (Trek), Roval (Specialized), and Giant all use DT Swiss guts in their high-end wheels.

The representative also stated that DT Swiss is the only brand licensed to make the Micro Spline driver, which means that other wheelset/hubset makers like Chris King, Stan’s NoTubes, and Industry Nine won’t be able to offer a compatible hub. At least for the foreseeable future.

But Plenty of Hubs

Shimano makes excellent hubs–really, its hubs don’t get the plaudits they deserve. And there are new hubs aplenty launching with XTR M9100.

All the new hubs get the Micro Spline cassette driver, use the Center-Lock disc rotor interface, and have a new clutch mechanism.

It’s called SCYLENCE because it offers silent coasting: the two halves of the driver mechanism completely disengage when the rider stops pedaling. Engagement is reasonably fast at 7.6 degrees.

The SCYLENCE rear hub is literally silent.

Matt Phillips

The HB-M9110/-B and FH-M9110/-B hubs are designed for J-bend spokes. They’re offered in Boost and non-Boost spacing, and in 28mm or 32mm drilling.

The HB-M9110-BS and FH-M9110-BS are compatible with straight-pull spokes. These are offered in only Boost spacing, just in 28mm drilling, and can be laced three-cross only.

Shimano is also introducing lower-cost MT900-series hubs. These are also offered for straight-pull or J-bend spokes, but only in Boost spacing.

Updated Pedals

The XTR pedals receive mild updates, but are otherwise the trusty and enduring Shimano SPD design.

The XC/gravel/cyclocross-focused PD-M9100 provides a wider platform than the previous generation M9000 pedal. It’s also offered in a second, 3mm shorter, axle for riders seeking a more road-like Q-factor, or to offset the additional width of some Boost-compatible cranks.

The new XTR Trail pedal offers better shoe support

Matt Phillips

The trail- and enduro-focused PD-M9120’s gets an expanded rear cage for better shoe support with “sneaker style” shoes.

Both pedals come with 1mm cleat spacers which help engagement with some shoes.

Still Mostly Metal

If you’ve lusted for XTR with more carbon, I have bad news: Only small bits of carbon are employed in XTR, in the rear derailleur pulley cage, brake levers, and some shifter bits. Shimano’s heritage is as a metal forging company: It’s arguably the best at it, and continues to turn out some impressive metal products that are equal–and often superior—to many companies’ carbon products.

Crank weights were not provided, but if they follow the usual script, I expect they will be extremely competitive in weight, stiffness, and durability against class-leading carbon cranksets.

No Di2…Yet

This group is being launched as a mechanical shifting group with no mention of a Di2 electronic group. However, I expect a Di2 version will be announced mid-year, if not sooner.

The Good Stuff: XTR Prices and Weights

Prices: XTR versus SRAM Eagle

Matt Phillips

Weights: XTR versus SRAM Eagle.

Matt Phillips

matt phillipsSenior Test Editor, BicyclingMatt is Bicycling’s senior test editor, and has been testing for Bicycling and its related titles since 1995.

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